"I've seen some sort-of handwringing about an indie bubble," The Fullbright Company's Steve Gaynor told the audience at D.I.C.E. 2014. People are saying "the bottom is going to fall out of indie games," he said.

That doesn't mean that things aren't going to get harder for indie developers, he cautioned. His studio's game, Gone Home, has already sold a quarter of a million copies, he said. But he also said that the window of opportunity to make a splash in the indie space may be closing.

"I do think we're in the middle of a sea change," Gaynor warned. "I feel like we are on the crest of this first wave of indie breakthroughs... I think that is going to mean something for people who are working on their first indie game now."

Games like Braid, Thomas Was Alone, Bastion, and Amnesia: The Dark Descent made waves. But the developers of those games are all preparing to release their second major titles: The Witness, Volume, Transistor, and Soma, respectively. There are many more examples, he said.

"The thing that I think is happening now that is going to make things interestingly different for indies that are trying to break in, in the next few years, is that the people who made these games are now making their follow-ups, and they are going to be made, marketed and perceived very differently," Gaynor said.

We're already seeing this change in "big ways," Gaynor said: Supergiant Games (Bastion) and Jonathan Blow (Braid) were both on stage at Sony's E3 press conference with their follow-ups, for example. Bastion sold 2.5 million copies, he noted, while The Witness has a budget Blow has estimated at $4 million.

"This is the world we're stepping into. Indies are much more in direct competition with each other," said Gaynor. "We're going to see a lot of indies that are competing with each other for the attention of the players, for the attention of the press."

The next wave of indies will have to be "more agile, more interesting," Gaynor said. "Showing us something we haven't seen is going to be more important than ever before."

This is exacerbated by another trend: "I don't think the bottom has fallen out of the industry, but the middle has fallen out of it," he said. Studios like Pandemic, or his former studio 2K Marin, have "dropped out" -- been downsized or shut down. This has left a vacuum for indies to fill, which lead to success. The problem is that this vacuum is quickly being filled, which leads to competition.

"There are hard realities," Gaynor said. However, he feels that indie community has a strength the triple-A industry lacks. "We all do want success for each other and we can all be a part of that," he said.

"That's the other side of the equation for me. Those of us who are fortunate enough that the press and the fans are excited about the next game... now have additional power to be able to funnel some of that attention to these smaller projects that are exciting, that are surprising, that could get lost in the shuffle," he said.